Multiresidue analysis of seven anticoagulant rodenticides by high-performance liquid chromatography/electrospray/mass spectrometry

Mice and rat populations are commonly controlled by two classes of rodenticide anticoagulants, coumarins and indandiones. However, poisoning of nontarget animals also often occurs. For cases such as these, a rapid, multiresidue method, which provides positive confirmation for both classes of anticoagulant rodenticides, is needed by diagnostic laboratories. A method was developed for the determination of seven anticoagulant rodenticides, coumafuryl, pindone, warfarin, diphacinone, chlorophacinone, bromadiolone, and brodifacoum, in diverse matrices, animal feed, cooked beef, and fruit-flavored beverages using high-performance liquid chromatography/electrospray/mass spectrometry. Detection was by MS/MS with electrospray ionization in negative mode. Confirmation was by retention time, m/z of molecular ion, and two parent-daughter transitions. Recoveries from selected the matrices ranged from 61 to 117%. Limits of quantitation were as low as 1.5-4.5 ng g-1. The developed method was rapid and provided the simultaneous confirmation and quantification of the seven anticoagulant rodenticides.     

Understanding the decline and extinction of monarchs (Aves) in Polynesian Islands

Understanding the decline and extinction of species has become critical to conservation biology. The five monarch species of the genus Pomarea, endemic to the southeastern Pacific, are all listed as threatened. Introduced mammals and birds are believed to be responsible for their rarefaction. We analyzed the historical and current distribution of monarchs and introduced animals and found no relation between presence of Polynesian rats (Rattus exculans) and monarch distribution. There was a highly significant correlation between the arrival of the black rat (Rattus rattus) and the decline and extinction of monarch populations. The extinction of monarch populations after colonization by black rats tended to take longer on larger islands than on smaller ones. On islands without black rats, monarchs persisted even where forests have been reduced by more than 75%. After an island was colonized by black rats the number of monarch pairs with young decreased dramatically. Eggs in artificial nests placed in sites used by monarchs were only preyed upon by black rats. No eggs were preyed upon by Polynesian rats (Rattus exulans) or introduced birds. Monarch nests were mainly placed on horizontal branches inside the canopy and were more accessible than nests of Polynesian warbler (Acrocephalus caffer), a species still locally abundant. Warbler nests were placed higher up on vertical branches near the top of trees. These studies suggest that nest predation by black rats has been the main cause of monarch decline. However observations of direct aggression of adult monarchs by introduced red-vented bulbuls (Pycnonotus cafer), especially when monarchs raise their young, suggest that introduced birds could aggravate the decline of monarch populations already weakened by black rats. We discuss the practical implications of these findings for monarch conservation.     

Pathogen exposure in endangered island fox (Urocyon littoralis) populations: Implications for conservation management

Island fox (Urocyon littoralis) populations on four California Channel Islands have declined severely since 1994. Canine distemper (CDV) was suspected to be responsible for the decline of the Santa Catalina Island fox, so knowledge of infectious disease exposure in the remaining island fox populations was urgently needed. This study reviewed previous pathogen exposure in island foxes and investigated the current threat by conducting a serologic survey of foxes on all islands and sympatric feral cats on three islands from 2001 to 2003 for antibodies against canid pathogens. Before the decline, foxes had evidence of exposure to CDV, canine adenovirus (CAV), canine parvovirus (CPV), and Toxoplasma, with exposure to these five pathogens differing greatly by island. Exposure to canine coronavirus (CCV), canine herpesvirus (CHV), and Leptospira was rare. In 2001-2003, wild-born foxes had evidence of exposure to CDV (5.2-32.8%) on 5 of 6 islands, CPV (28-100%) and CAV (4.7-100%) on five islands, and Toxoplasma gondii (2.3-15.4%) on four islands. Exposure to CCV, CHV and Leptospira was less common. Sharing of infectious agents between sympatric foxes and feral cats appeared minimal, but CDV exposure was detected in two cats on Santa Catalina Island. Domestic dogs have historically been present on the islands, but it is not known if canine diseases can be maintained in fox populations without the continual presence of dogs. Targeted vaccination programs against the most virulent pathogens and continued intensive disease surveillance may help protect the critically small remaining fox populations from disease outbreaks that could threaten the success of ongoing conservation efforts.     

Prioritizing rat eradication on islands by cost and effectiveness to protect nesting seabirds

To prioritize conservation actions on Italian islands we used the case study of the eradication of the Black rat Rattus rattus to protect Cory’s shearwater Calonectris diomedea and Yelkouan shearwater Puffinus yelkouan. We evaluated for each island the effectiveness of rat eradication by means of two different indices, both based on the relative importance of the island’s nesting population of the two species at the national and regional scale, but differing in the parameters set at the divisor, i.e., respectively, the number of nesting pairs in rat-free islands and the number of islands occupied by shearwaters. We estimated analytically the monetary costs of rat eradication on each island. Islands at high risk of recolonization were excluded from further analyses, while costs and effectiveness of rat eradication were compared for the remaining islands. Rat eradication was most cost-effectively carried out on the island hosting the largest colony of P. yelkouan. Eradicating rats from all the islands in the ranking provided benefits to 63.9% of the Italian population of P. yelkouan, but only to 7.1% of that of C. diomedea. Comparing costs and effectiveness of all possible island combinations, ranging from a minimum budget of 50,000 € and a maximum of 1600,000 € (i.e. the cost for eradicating rats from all the listed islands), the maximum increase in effectiveness (marginal effectiveness) fell around a relatively small budget (200,000 €). For both species, when adopting the cost/effectiveness rankings, the number of pairs protected for 1000 € of investment was significantly higher than adopting rankings of effectiveness alone, demonstrating that conservation priorities are more efficiently identified by including monetary costs in the analysis.     

Effects of Key deer herbivory on forest communities in the lower Florida Keys

Ungulate herbivory can have strong impacts on plant communities, but these impacts are rarely considered in recovery plans of endangered species. This study examined the effects of the endangered Key deer (Odocoileus virginianus clavium) on its environment in the lower Florida Keys. The Key deer population has increased to over 700 deer from approximately 50 deer in the 1950s; however, approximately 75% of the population resides on only a few islands (Big Pine, No Name, Big Munson) where Key deer herbivory on forest communities may be substantial. Effects of deer herbivory on plant densities were estimated on these islands using vegetation quadrats in hardwood hammock, buttonwood transition, and mangrove wetlands and compared to nine other islands with intermediate or low deer densities. On islands with high deer density, densities of preferred woody plant species <1.2 m tall (within Key deer reach) were significantly lower than islands with lower deer densities, while densities of some nonpreferred species were significantly higher. Deer exclosures established in hardwood hammock on a high-density deer island revealed a mean increase in abundance/height of preferred woody species inside exclosures, while nonpreferred species significantly increased in open plots. We conclude that on high deer density islands, highly preferred plant species might eventually fail to regenerate and unpalatable plant species may become dominant. Careful criteria need to be developed to maintain Key deer numbers above an endangered species status yet below levels that are destructive to local forest species.     

Husking stations provide evidence of seed predation by introduced rodents in Tongan rain forests

The islands of Tonga, in Western Polynesia, lacked rodents prior to human colonization. During the past 3000 years, people have introduced three species of rats (Rattus). Seed predation by rodents structures plant communities in many parts of the world. Therefore, there is the potential for rats to have a significant impact on the regeneration of plant communities in Tonga. We found 53 husking stations—sheltered sites used by rats to strip inedible protective structures (husks) from the seeds they eat—on eight islands in Tonga. The stations contained 13,555 empty husks from at least 18 plant species, but only 165 viable seeds and seedlings. These husking stations provide evidence of seed predation by rats. Determining the extent to which seed predation threatens plant regeneration will be important for conservation of native forest remnants.     

Ecology and conservation of two endangered subspecies of the leopard cat (Prionailurus bengalensis) on Japanese islands

The conservation of rare species on islands is a special challenge, especially when the islands are faced with increasing human impact. Two endangered wild felids in Japan provide a contrast that is useful for examining conservation strategies. The Iriomote cat (Prionailurus bengalensis iriomotensis) is endemic to Iriomotejima Island in Okinawa, and the Tsushima leopard cat (Prionailurus bengalensis euptilurus) occurs in the Tsushima islands in Japan, although a related subspecies found in the Korean Peninsula. Population size was approximately 100 individuals for each subspecies. While the population of Iriomote cat appears relatively stable, the population and abundance of the Tsushima leopard cat has decreased in recent decades. Because of their small population sizes and restricted habitats both are listed as endangered species/subspecies in Japan’s Red List, and the Iriomote cat is listed as an endangered subspecies in the IUCN Red List. Although both are similar-sized felids living on small islands, their ecological characteristics such as food habit, habitat selection, and density differ. These differences seem to be caused by the climate, the biological environment (the species composition of fauna in each island, and the presence of competitors), and the artificial background. The threats facing these two felids are also similar. Habitat destruction, traffic accidents, and negative influences by introduced species are the principal threats to be addressed for their conservation. At the same time, there are differences in the degree of impact by each threat, in each species’ conservation programs in practice, and in the stages of progress and operation of programs. These differences are partly because they have different ecological features and partly because the social background of each island, such as human population, main industry, and historical relationship between human and wildlife, are quite different. We will compare the ecology and state of these two wild felids and discuss the different conservational situations in relation to felid ecology and human society.     

Insular pest control within a metapopulation context

Introduced pests threaten many species and their control is generally beneficial for conservation, particularly on islands where complete eradication is possible. Unfortunately on ‘nearshore’ islands neighbouring source populations exist and unaided reinvasion is likely. Pest control programmes at these sites thus require a metapopulation context to adequately manage movements between source and sink populations. We investigated the ecology of introduced ship rats (Rattus rattus) on a nearshore island, and gene flow with adjacent mainland populations, in order to understand the metapopulation dynamics and relative levels of pest control required within the landscape. We sampled the entire population by trapping (n = 30), achieving eradication, and found a low rat density (3.2 ha⁻¹) indicative of a sink population. Seed and other plant material constituted the major dietary component of rats. Despite its proximity to mainland source populations, the island population was genetically distinct with reduced allelic diversity caused by a recent reinvasion founder effect. Genetic analyses also detected recent migrants between the populations. In contrast, two mainland populations separated by a similar distance displayed complete genetic mixing. The small water gap therefore provides a sufficient barrier to lower the migration rate to the island and delay reinvasion, which nonetheless eventually happens. In order to maintain nearshore islands pest-free, conservation management will require a metapopulation approach simultaneously focusing on both island and source population pest control.     

Biodiversity conservation in tropical forest landscapes of Oceania

The fragmented island realm of Oceania includes a relatively small proportion of the world’s tropical forests, but those forests support unusual richness of narrowly endemic species. In common with tropical forests across most of the world, tropical forests in Oceania are declining due to factors associated with increasing human population size, economic drivers and more intensive exploitation. In parts of Oceania, forests are being cleared at unsustainable rates, and replaced with far simpler ecosystems of timber or food crops. To a small degree, the present-day biodiversity of tropical forests in some parts of Oceania may be predisposed to such disturbance, given a history of natural disturbance (particularly through cyclones), and of smaller-scale slash-and-burn agriculture or landscape-scale burning. But, in most places, the current intensity, scale and/or rate of modification far surpass their precedents, and biodiversity is consequently diminishing. Tropical forests in Australia may be an exception to this trend, with now reasonably effective protection. However, more so than for tropical forests in most other continents, the major biodiversity conservation challenges for tropical forests in Oceania are extrinsic. Introduced plants, animals and diseases have collapsed ecological communities through much of Oceania, homogenising the biota from a series of highly distinctive and localised species assemblages to a more impoverished set of ubiquitous disturbance-tolerant exotic species. In many islands, this simplification has occurred regardless of the extent of native forest remaining, such that retention and reservation of primary forest is an insufficient conservation action. The fate of biodiversity in Oceania is also likely to be much affected by climate change, an unbalanced consequence given the region’s relatively small contribution to greenhouse gas emissions. Future hope for biodiversity conservation in tropical forests of Oceania lies in the renewed application of some traditional management constraints, the appropriate delivery of international support (such as may be available through carbon markets), improved quarantine processes, and through some protection naturally offered by the remote scattering of the islands that comprise Oceania.     

The ecology and conservation of reptiles on Round Island and Gunner's Quion,Mauritius

The reptile communities on two islands off the north coast of Mauritius are described. One of these islands, Round Island, is the last refuge for four species: Phelsuma guentheri, Leiolopisma telfairii, Bolyeria multocarinata and Casarea dussumieri, which together with four more species form a relict herpetofauna of great scientific and conservation interest. The reptile fauna of the neighbouring island of Gunner's Quoin has been reduced to four species, probably because of habitat destruction and the effects of ship rats Rattus rattus. Round Island has also suffered habitat destruction through introduced mammals but because of its remoteness, rats are absent. Conservation of the Round Island ecosystem is discussed; removal of the remaining alien herbivores, the rabbit Oryctolagus cuniculus and conservation education about Round Island are the main recommendations.     

Assessing the risks of introduced chickens and their pathogens to native birds in the Galápagos Archipelago

Poultry production is an important economic activity on inhabited islands of the Galápagos archipelago. There has been a recent surge in both small-scale backyard chickens and larger scale broiler production associated with growth in the human population and the tourist industry. With increased poultry production, concerns have been expressed about the increasing risk of transfer of disease from chickens to native Galápagos bird species that may have little resistance to introduced pathogens [Wikelski, M., Foufopoulos, J., Vargas, H., Snell, H., 2004. Galápagos birds and diseases: invasive pathogens as threats for island species. Ecology and Society 9(5). Available from: URL:http://www.ecologyandsociety.org/vol9/iss1/art5]. This study evaluates risks posed by chicken disease to endemic and native Galápagos bird species, based on empirical evidence of pathogens present in chickens on the islands and a literature review of effects of these pathogens in wild species. Pathogens identified in domestic chicken populations of immediate avian conservation concern are Newcastle disease, Mycoplasma gallisepticum, and the proventricular parasite Dispharynx sp. Newcastle disease (avian paramyxovirus-1) poses an imminent threat to Galápagos penguins (Spheniscus mendiculus), flightless cormorants (Phalacrocorax harrisi), and lava gulls (Larus fuliginosus), species with very small population sizes (less than 1500 animals each). Additionally, litter from broiler farms could affect ecological processes in local ecosystems. Improved poultry biosecurity measures are urgently needed on the Galápagos Islands for avian disease management, yet developing these strategies presents political, social, and economic challenges.     

Avoiding aliens: Behavioural plasticity in habitat use enables large, nocturnal geckos to survive Pacific rat invasions

Rodents are efficient invaders on a global scale and pose a significant threat to native biotas, particularly in systems such as oceanic islands which support a reduced suite of mammals. Pacific rats (Rattus exulans) are implicated in extinctions, range restrictions and declines of vulnerable endemic faunas throughout the Pacific. However, research into the behavioural and ecological modifications that enable native species to persist in the presence of Pacific rats is scant. We examined the population structure, behaviour and microhabitat use of Duvaucel’s geckos (Hoplodactylus duvaucelii; radio-telemetry), and Pacific rats (spool-and-line tracking) on three New Zealand offshore islands with different histories of rat incursions and eradication: (1) Green Island, historically rat-free, (2) Korapuki, from which rats were eradicated 20 years ago, and (3) ōh?¯nau, before and 6 months after rat eradication. Although Pacific rats and Duvaucel’s geckos shared habitat at a broad spatial scale, little overlap in micro-habitat use existed where they were sympatric. In the presence of rats, Duvaucel’s gecko capture rates and recruitment were reduced. However, 6 months after rat eradication, and prior to any recruitment, capture rates of adult geckos increased fourfold and geckos were using a greater proportion of habitat preferred by rats. Thus, we provide strong empirical evidence that Pacific rats ecologically displace Duvaucel’s geckos. Highly plastic spatial avoidance behaviour by native prey species in response to the presence of introduced rodents may enable geckos to persist in sympatry with rodents at least in the short-term.     

Conservation action in the Galàpagos: feral pig (Sus scrofa) eradication from Santiago Island

Introduced mammals are major drivers of extinction and ecosystem change. As omnivores, feral pigs (Sus scrofa) are responsible for wholesale adverse effects on islands. Here, we report on the eradication of feral pigs from Santiago Island in the Galápagos Archipelago, Ecuador, which is the largest insular pig removal to date. Using a combination of ground hunting and poisoning, over 18,000 pigs were removed during this 30-year eradication campaign. A sustained effort, an effective poisoning campaign concurrent with the hunting program, access to animals by cutting more trails, and an intensive monitoring program all proved critical to the successful eradication. While low and fluctuating control efforts may help protect select native species, current eradication methods, limited conservation funds, and the potential negative non-target impacts of sustained control efforts all favor an intense eradication effort, rather than a sustained control program. The successful removal of pigs from Santiago Island sets a new precedent, nearly doubling the current size of a successful eradication, and is leading to more ambitious projects. However, now we must turn toward increasing eradication efficiency. Given limited conservation funds, we can no longer afford to spend decades removing introduced mammals from islands.     

Threats to dragonflies on land islands can be as great as those on oceanic islands

We ask whether oceanic islands and equivalent-sized continental blocks, which we call here ‘land islands’, are similar or not in their species richness, number of range-restricted species, and in number of threatened species. We used sites in southern Africa and islands in the Western Indian Ocean. We chose dragonflies as they are taxonomically tractable, well surveyed, and provide a range of characteristics from narrow-range endemics to widely-spread and vagile opportunists. We then selected as many oceanic islands as possible where there were sufficient data to make comparisons with land islands of a similar area in African savanna, grassland and mountains rich in endemic species. Generalized Linear Mixed Models were used to analyse the overall, range-restricted and threatened species richness for all islands (both oceanic and land) and then for the two types of island separately. Species richness increased with island size, with oceanic and land island size relationships being similar. Land islands overall had significantly more range-restricted species. Species on land islands were as threatened as those on oceanic islands. However, the land islands of the Western Cape were under a higher level of threat than oceanic islands of comparative size. The large islands of Madagascar and Sri Lanka were outliers with very high levels of threat. Translated into conservation, the results illustrate that over-generalizations about island faunas being more threatened than continental ones are not necessarily valid. While not wishing to draw attention away from the urgent conservation action needed on many tropical islands, we argue that comparisons of oceanic versus land islands detract from the more urgent task of local conservation action based on the special needs of any particular area, whether land or oceanic. It is more meaningful to establish how threats operate and how to mitigate them on small populations rather than focusing purely on any particular island type per se.     

Damage by rats Rattus norvegicus to breeding birds on Danish islands

Occurrence of rats Rattus norvegicus was recorded in Danish islands during the period 1970–1979. Rats apparently became common during the 1960s and 1970s. Their frequency fluctuated, indicating a possible 4-year cycle. Most rat colonisations lasted a single year. Geographical differences in their frequency may be caused by regional differences in distribution of larid colonies. Rat distribution did not follow the pattern suggested by the theory of island biogeography; presence of larids may be of major importance. When rat populations in hedges, ponds and streams are at maximum population density in autumn, pregnant females emigrate to, and so colonise, islands. Flooding and the severity of the winter may cause extinction. Food supply and predation may be of importance in limiting rat numbers. Breeding birds suffer, especially those placing their nests near rat runs; rat predation on adults may have serious consequences for a long-lived species, whereas that on eggs and young is insignificant. Some larid species renest in the immediate vicinity when predated by rats; others desert their dense colonies. Rat control is successful in small islands, whereas large island populations are only exterminated with difficulty. They should be controlled to prevent predation and to keep breeding grounds usable. This should be done in late winter when population density is low and food-supply insufficient.     

Invasive rats alter assemblage characteristics of land snails in the Ogasawara Islands

Although a large number of studies have shown that rats have a serious effect on island ecosystems, questions remain regarding how their invasion alters native species diversity and assemblage patterns on islands. In particular, a long history of invasions makes it difficult to understand the impact of rat invasion. In the present study, I investigate how an increase in predation by black rats (Rattus rattus) alters the assemblage characteristics of land snails on the Ogasawara Islands in the West Pacific. Radical declines in many land snail species have occurred since 2006 due to increasing predation by black rats. The frequency of shells with predation scars was greater on larger species and on those living on the trees and in a shallower position in the litter, suggesting greater predation pressure on these species. As a result of this selective predation, large species living on trees and in shallower parts of the litter declined. Accordingly, when black rats increased on the island, small species and species with a burrowing microhabitat became dominant in the land snail assemblage. The present findings can be used to aid in predicting the effects of rat eradication and in estimating the assemblage patterns and diversity prior to rat invasion.     

Sampling on private property to evaluate population status and effects of land use practices on the gopher tortoise, Gopherus polyphemus

Although private properties are predicted to play an increasingly significant role in conservation, surveys of species of special concern are rare on these lands. We created a template for a multi-county survey of randomly selected sites and sampled for burrows of the gopher tortoise (Gopherus polyphemus) in south-central Georgia, USA. Current land use was strongly correlated with tortoise population condition. The highest densities of tortoise burrows were found on lands with open-canopied pine stands that were managed with prescribed fire, a practice associated with types of selection forestry and/or wildlife management. Agricultural sites and unburned areas provided poor habitat and pine plantations were only slightly better. Our estimates of tortoise population densities indicated that the current landscape supports less than 20% of the animals present before implementation of modern land use practices. In addition, our estimate for density of active burrows was approximately one third of that projected for the entire state range 20 years ago by Auffenberg and Franz [Auffenberg, W., Franz, R., 1982. The status and distribution of the gopher tortoise (Gopherus polyphemus). In: Bury, R.B. (Ed.), North American Tortoises: Conservation and Ecology (US Fish and Wildlife Service Wildlife Research Report 12). pp. 95-126]. However, some good sites for gopher tortoises remain in south Georgia and our data also suggested that extraordinary conservation actions may not be required if ways can be developed to retain traditional land management practices on private property.     

High levels of hatching failure in an insular population of the South Island robin: a consequence of food limitation?

Endangered birds in insular environments like New Zealand are often translocated to predator-free offshore islands for conservation purposes. Some translocated populations however exhibit reduced fecundity, and it has been suggested that either inbreeding (due to small number of founders) or resource shortages (due to high population density) may limit reproductive success. For example, the South Island robin (Petroica a. australis) population on Motuara Island (59 ha) was founded by only five birds but has increased to ∼600 individuals, or a density >10 times that of the mainland. Despite this apparent success, the rate of hatching failure in this population is three times higher than in mainland populations, with more than a third of eggs failing to hatch. To test if elevated hatching failure is the result of food limitation, we carried out a food supplementation experiment by providing females with mealworms equivalent to ∼50% of their daily energy requirements. Food supplementation had no effect on hatching success, clutch size, incubation attentiveness or nest size. Egg volume increased with food supplementation in one of the two years of this study, but both egg volume and incubation attentiveness were unrelated to rate of hatching failure. As previous genetic analyses confirmed that the bottlenecked population of robins on Motuara Island have significantly less genetic variation than their source population, we conclude that inbreeding depression, and not food limitation, is the most likely explanation for their high rate of hatching failure. We suggest that the experimental translocation of genetically dissimilar individuals be considered as a possible remedy for low productivity in island populations that were initiated with few founders.     

Efficiency of conservation shortcuts: an investigation with otters as umbrella species

The use of shortcuts is widespread in conservation practices to help ensure biodiversity conservation with minimal expenditures. An umbrella species is a species whose conservation confers protection to a large number of naturally co-occurring species. The aim of this study is to test the usefulness of the umbrella species concept for conservation management. As our umbrella, we chose a wide-ranging and flagship species, the European otter (Lutra lutra). Otters are widely distributed predators with numerous genera and species, so otter occurrence could virtually be used as “umbrella” in every freshwater habitat. To test the usefulness of the concept, we investigated whether an umbrella species might protect other species in the long term. We compared (1) bird and amphibian species richness in 1993 and in 2003 on nine sites where otters were monitored for 20 years, and (2) bird, amphibian and mollusc species richness between the previous sites and nine bio-equivalent sites where no otter occurrence has been detected for 20 years. The study was carried out for two spatial scales: total otter home range and core areas (most intensely exploited areas). Our results show that species richness was significantly different between years on sites inhabited by otters. However, we showed that biodiversity did not differ between pairs of bio-equivalent sites inhabited or deserted by otters, whatever the estimation method. Our results cast doubt on the validity of umbrella species use as an objective tool for conservation. However, the keystone functional role that otters could play in ecosystems might be an interesting way to reconsider the purpose of the umbrella species concept.     

Identifying and mapping biodiversity processes for conservation planning in islands: A case study in Réunion Island (Western Indian Ocean)

Over the last century, island biodiversity has become one of the most threatened in the world. Although many island conservation plans address biodiversity requirements at the species level, few plans address the spatial requirements of the biodiversity processes that underpin the persistence of these species. Using systematic conservation planning principles, we map the spatial components of biodiversity processes (SCBPs) and use these to design broad-scale conservation corridors for Réunion Island. Our method is based upon a literature review, expert knowledge, spatially explicit base data, conservation planning software, and spatial modelling. We combine a target-driven algorithm with least-cost path analyses to delineate optimal corridors for capturing key biodiversity processes while simultaneously considering biodiversity pattern targets, conservation opportunities, and future threats. We identify five SCBPs: the oceanic-terrestrial interface; riverine corridors; macrohabitat interfaces; the boundaries of isolated topographic units; and lowland-upland gradients. A large proportion of the SCBPs (81.3%) is currently untransformed, whereas 3% is irreversibly transformed by urbanisation and 15.7% is transformed but restorable. However, SCBPs are almost fully disrupted by urbanisation in the lowlands, thereby compromising functional corridors along full altitudinal gradients. This study is a contribution toward the reconciliation of conservation versus development objectives on Réunion Island but we believe that the delineation method is sufficiently general to be applied to other islands. Our results highlight the need for integrating marine, coastal and terrestrial conservation planning as a matter of urgency, given the rapid transformation of coastal areas on islands.